Environmental geohydrochemistry and health of the high altitude population in Ladakh

Background： Radiographic signs of Pneumoconiosis found in farming Ladakhi despite absences of mines and industries were believed to be due to exposure to frequent dust storms and domestic fire pollutions. Seasonal Koilonychia （spoon nail） occurring predominantly in farming women in absences of iron deficiency anaemia was thought to arise from exposure to water made alkaline by weathering of hornblende minerals. The relation of these health conditions to environmental geohydrochemistry is postulated as the source of irrigation water in the affected population originates from glaciers in trans-Himalaya range of sedimentary geology and steep landscape favouring flushing of silica/silicate containing silts. Methods and results： Survey in two central Ladakh villages revealed radiographic evidence of silicosis in all middle aged women and half in middle aged men. In a large-scale study of 3105 subjects aged over 30 years from three villages; 101 （22.5%） of the 449 radiographed showed signs of pneumoconiosis （ILO 1980 criteria） including eggshell calcification of hilar gland and progressive massive fibrosis. Indoor dust analyzed using Philips 400T electron microscope with energy dispersive analysis system attached showed SiO2 levels upto 53.27% with particle size of 0.5 to 5.0 microns and the concentration during cooking period in the worst affected area was 7.495 mg/m^3. Microscopy and histopathology from the subject was characteristic of pneumoconiosis. Analysis of the inorganic dust in the lung showed 40.2% muscovite, 37.3% quartz with the extracted dust wt 147.9 mg/gm of dry tissue. Prevalence of chronic cough with chronic phlegm and percentage of villagers with FEV1/FVC ratio of less than 65% rose with age. Of 70 subjects studied 19 women and 2 men had Koilonychia with incidence being highest in summer. Absence of seasonal Koilonychia in villages fed by water derived from northern mountain range glaciers with mainly igneous geology supports our hypothesis.     

Natural siliceous dust and human health： Pathways, toxicity, and impact

Fine atmospheric dust includes mineral particles and aggregates, fibrous minerals and fibrous organic material. Generation, dislodgement and transport （deflation） of natural dust with the finer （〈4 microns） components suspended as silt-size aggregates, is widespread in and adjacent to the world＇s drylands, as well as deriving from volcanic vents. Silica is a highly fibrogenic agent in lung tissue. Long-term inhaling of siliceous dusts can lead to a number of fibrotic lung diseases, including natural （non-occupational） pneumoconioses （notably silicosis, but including asbestosis and others）. Different polymorphs of silica show different levels of toxicity in interaction with lung tissue. Particles with highly active surfaces may release radicals, causing cell damage. Some types of inhaled particulates are degraded by macrophages, but many are highly resistant and persist in the lungs, some stimulating fibroblastic cells to deposit collagen. Silicosis is an inflammation of the lung commonly caused by silicate mineral particles, leading to fibrosis. Three types are recognized： nodular pulmonary fibrosis （simple or chronic silicosis）, acute silicosis, and accelerated silicosis. Generally, finer particulates have greater oxidative capacity than the coarser fractions. They contain more reactive oxygen species, their greater bioreactivity making them more toxic to pulmonary tissue. Nevertheless, inhalation of large dust particles （〉 10μm） may constitute a health risk if the mineralogy is toxic, regardless of where the grains lodge in the respiratory system. Dust may absorb harmful gases, disease-generating bacteria and carcinogenic hydrocarbon compounds. Silica-related respiratory disease may also an exacerbate cardiac problem, and epidemiology suggests a link with tuberculosis. Quantification of dust loading and exposure requires study of spatial and temporal patterns, supported by meteorological analysis, airflow modeling and satellite-borne imagery. Some acute, short-term health impacts have been assessed using atmospheric and health records both before and after a dust storm or by comparison of populations within and outside such events. Analysis of the size, shape, mineralogy and geochemistry of ambient dust particulates provides information on natural dust sources, dust concentrations, and potential particulate toxicity, as well as providing a datum for assessment of human exposure levels.     

Methylmercury and human biomarkers： Questioning the evidence

Methylmercury （MeHg） is a powerful neurotoxicant in humans. In terms of biomarkers of MeHg exposure, hair and blood have long been used in epidemiological studies as the biomarkers of choice. In fact, total hair mercury （Hg） content as well as organic blood Hg concentrations reflects exposure to organic Hg from food consumption. Extensive studies, establishing a constant and linear relation between MeHg intake versus Hg levels in hair and blood, were conducted by governmental officials to establish guidelines on safe levels of MeHg exposure, which were translated into threshold daily fish consumption rates （usually expressed as μg MeHg per kg bodyweight）. Nowadays, in most epidemiologic studies blood or hair mercury （Hg） level is commonly used as a valid proxy to estimate human exposure to methylmercury （MeHg） through fish consumption without relating this signal to actual fish consumption patterns among populations. Human variability in mercury toxicokinetics was identified and measurement error has been pointed out to be a substantial contributor to observed variability, particularly where dietary information is retrospective and self-reported. However, experimental evidence indicates that significant variability among individuals may exist in the biokinetics of mercury. Also recent findings from previous population-based studies through COMERN initiative also revealed that MeHg metabolic processes might greatly vary across populations. In fact, it is unlikely that the magnitude of the difference measured between observed and expected levels of mercury, given the reported intake, can be entirely explained by laboratory measurement errors or reporting bias.     

矿产资源对人体健康的影响及其对策--以四川省为例

随着社会的发展,人类对矿产资源的需求量日益增大.而某种程度上,一些国家或地区的环境污染状况,总是与这些国家和地区的矿产资源的富集程度、开发和利用水平相关联,以下就四川省矿产资源对人体健康影响及其对策加以分析.1 四川省矿产资源和人口密度分布特点四川境内分布的矿产资源中22种元素和矿种对人体健     

农药污染对人体健康的危害及防治

我国是使用农药最早的国家之一，有着十分悠久的历史，农药用于防治农林牧业病、虫草害、鼠害和其他有害生物是调节植物生长的药物及加工制剂。大量的事实表明，农药在防治病虫害、保护庄稼生长方面的作用不容置疑。从不使用农药的自然农业发展到使用农药的现代农业，农药做出了一定的贡献。据统计，世界粮食因为农药的实用，产量相对增长，但如果不使用农药，因为病、虫、草害的影响，粮食将减少1／3[1]。由此可见，农药在人类农业史中起了十分重要的作用。但是由于农药是一种化学制剂，长期大量使用，会对环境生物安全和人体健康产生不利的影响。农药怎样污染环境和对人体健康产生危害，笔者就这一问题加以论述。     

地震模拟振动台振动对建筑物中人体的舒适感的影响分析

本文给出了一种地震模拟振劝台振运对建筑物中人体的舒适感影响的分析方法，并结合实例进行了具体分析。文中给出的分析方法和实例计算结果对于地震馆的设计有一定参考价值。     

浅谈农业地质环境与人体环境

农业地质环境泛指岩石－土壤和水。农业地质环境是人类持续生存与依赖的环境。农业与环境污染通过食物链给人类生存和发展带来影响，生态环境与人类生存的发展有着依存关系。     

陕西省区域环境地球化学分区

为了利用地壳元素分布特征与动植物微量元素含量间的关系,指导生态环境综合治理,借助已有的基础地球化学资料,进行陕西省地球化学分区,确定各分区的环境背景值、污染起始值、缺乏临界值、过剩值临界值,并将陕西省分为陕北、关中、陕南3个地球化学区,圈定了1个元素贫化区和2个元素富集区。提出应该在元素的缺乏和过剩的异常区内进行生物体内微量元素含量的定期检测。做到对地球化学疾病及时发现及时寻找对策,以保证人类生存环境的安全,提高生存质量。